WASHINGTON: President Barack Obama denounced waterboarding, offered cautious hope on the economy and looked to calm fears about swine flu as he held a major White House news conference to mark his 100th day in the White House.

Obama also gave assurance that one way or another, Pakistan's nuclear arsenal would not fall into the hands of Islamic extremists. He said he was confident "primarily, initially" because he believes Pakistan will handle the issue on its own. But he left the door open to eventual US action to secure the weapons if needed.

The wide range of issues raised at Wednesday's news conference captured the whirlwind of Obama's first 100 days. Obama has had to deal with two wars, the deepest recession in decades and, most recently, the swine flu outbreak, even as he pushes to overhaul health care, energy and education policies.